Russian air raids against terrorist positions in Syria have resulted in a swift decline in oil sales by the terrorist group ISIS, says a French official.

ISIS-controlled oil sales “have declined significantly in recent weeks due to the Russian campaign in Syria,” Russia’s Sputnik quoted a French National Assembly Defense Commission member, Nicolas Dhuicq, as saying on Saturday.

Apart from selling crude oil, the group also “pays people to refine oil in its own places,” he noted, adding, the majority of the terrorist group’s oil revenue is from countries such as Saudi Arabia, Turkey and Qatar.

“ISIS is funded, probably, by Saudi Arabia and Qatar, which are trying to gain back their share of influence in the regions of Iraq and Syria against Iran. Until now, ISIS continues to receive money from these countries, most likely from private donors,” said Dhuicq.

He estimated that the militant group’s budget was around $2 billion, adding further that donors from Turkey also had a hand in re-selling crude oil obtained from ISIS.

“Money may also come from the secret services of the countries and also from Turkey,” he noted.

The Takfiri group currently controls parts of territory in Syria, Iraq and Libya, where it carries out heinous acts of terror such as public decapitations.

Russia launched its first airstrikes against the Takfiri terrorists in Syria on September 30 at the request of the Damascus government. Moscow says its air raids are meant to weaken ISIS and other terrorist groups that are wreaking havoc in Syria; Press TV reported.